1. Field of the Invention
The present invention relates to an elastomer bush bearing according to the preamble of the independent claim. More particularly, the invention relates to a bush bearing, wherein the bearing body is encapsulated by axial flanges of the outer sleeve of the bearing and wherein the bush bearing has an elastomer bearing body with a particular profile extending in the axial direction.
2. Description of the Related Art
Elastomer bush bearings, which are employed frequently in the automotive engineering for supporting chassis components, consist essentially of a cylindrical or tubular metallic inner part, an elastomer bearing body which concentrically surrounds the inner part, and an outer sleeve receiving the inner part with the bearing body. The elastomer bearing body, for example, a rubber spring, is generally adheringly connected at least with the inner part by vulcanization. In several embodiments of corresponding bearings and depending on the respective application, the generally also metallic outer sleeve has a flange or flanges on its axial ends. Forming a flange of the axial ends provides, for example, axial limits stops and axial flanges as well as an axial retaining element, which prevents the bearing body from slipping out of the outer sleeve when an axial load is applied. The flange is also prevents contamination from entering the bearing. A bush bearing having an outer sleeve with flanged axial ends is disclosed, for example, in the form of a bearing with hydraulic damping in DE 101 18 229 A1.
Bearings are also known for achieving a radial damping characteristic that varies in the circumferential direction of the bearing, wherein the bearing body is suitably profiled or wherein the circumference of the bearing body has sections with recesses or is exposed with respect to the bearing sleeve. Corresponding bearings are disclosed, for example, in DE 198 59 067 A1 or DE 100 04 936 A1. The bearings described in the aforementioned published applications, however, do not have a flange formed on the outer sleeve. DE 601 06 767 T2 discloses an elastic joint wherein the end faces of the bearing body are contoured with a wave-like and simultaneously helical pattern for obtaining regions with different radial stiffness in the circumferential direction. The helical twist of the end-face contours of the bearing body of the corresponding joint is optimized, in particular, for torsional loads, wherein the outer sleeve, like in the two aforedescribed bearings, does not have a flange.
As already described, the axial ends of the outer sleeve of a rubber bearing are flanged, for example, for realizing an axial retaining element. Due to the flange, such bearings have a relatively high radial stiffness, accompanied by a high axial stiffness. These in bearings are capable of supporting high radial loads due to the high radial and axial stiffness and the encapsulation of the rubber body. However, in certain applications a corresponding bush bearing may be required to support high radial loads, but should at the same time still have a smaller radial stiffness and a softer radial spring characteristic, for example when radial oscillations with smaller amplitudes are introduced. The smaller radial stiffness can be easily achieved by appropriate selection of the elastomer material forming the bearing body. However, as long as the bearing is still subjected to high radial loads, there is still a risk that the bearing body, or the rubber body, expands partially across the flange out of the bearing body, allowing the expanding material to be sheared off at the flange under the load. This disadvantageously reduces the service life and stability of the bearing.